Referring to FIG. 1 to 3, as disclosed in T.W. patent application No. 087216147, publication No. 392975, an electrical connector 1 is a zero insertion force (“ZIF”) electrical connector for electrically interconnecting a central processing unit (“CPU”) and a mainboard used in computer device. The electrical connector 1 comprises an insulative housing 10 and a plurality of conductive terminals 2. Each of the conductive terminals 2 electrically connects with the circuit board 30 through surface mounting technology (“SMT”) by pre-setting a solder ball 23 onto an end thereof.
The insulative housing 10 of the electrical connector 1 has a mounting surface 12 on the bottom surface thereof which is positioned proximate to the circuit board 30 and a receiving surface 11 on the top surface thereof for supporting the electronic component. The insulative housing 10 also defines a plurality of through holes 13 extending between the mounting surface 12 and the receiving surface 11.
Each of the conductive terminals 2 respectively received in the corresponding through holes 13 forms a contact portion 20 extending toward the receiving surface 11 and an end portion 21 opposite extending to the mounting surface 12. The end portion 21 has a bottom surface 22 for soldering with the corresponding solder ball 23.
To improve the success rate of pre-setting the solder ball 23 onto the end portion 21 of the conductive terminals 2, the end portion 21 forms a disk-shape plane approximately 90 degrees bending to the contact portion 20 so that the end portion 21 and the mounting surface 12 of the insulative housing 10 are approximately located in the same plane. The plane disk-shape end portion 21 provides a larger area of pre-setting the solder ball 23 so as to steadily pre-set the solder ball 23. In addition, a plurality of protrusions 25 is integrity extending from the side of the end portion 21 for preventing the solder ball 23 dropping from the bottom surface 22 of the end portion 21.
To applying the SMT of pre-setting the solder ball 23, one end of the conductive terminal 2 must have a structure of easily locating and connecting the solder ball 23. The above method is only one of the resolving schemes with which the end portion of the conductive terminal 2 has different structures to locate and connect the solder ball 23. The present invention provides an improved conductive terminal to locate and connect the solder ball 23.